Are heavyweight buildings more comfortable? The potential of thermal mass in increasing thermal comfort

Paper in proceeding, 2017

In temperate climates, one passive design solution is to increase the heat capacity of building fabric. This design principle aims to reduce heating demand in winter and over-heating in summer; it is also coupled with more stable indoor air and radiant temperature. This may suggest that by exposing thermal mass, occupants may feel more comfortable. Although previous research based on simulations have studied this relationship, there is a lack of empirical evidence. This paper reviews the results an EU-funded research project, smart controls and thermal comfort (SCATs) to ascertain the impact of building fabric on occupants’ perceived comfort. Between 1997 and 2000, twenty-six office buildings from five different countries (France, Greece, Portugal, Sweden and UK) were surveyed using a transverse questionnaire, a longitudinal questionnaire and environmental monitoring. This paper analyses the transverse questionnaires responses (N=451), in particular answers to questions on thermal perception, thermal preference and overall comfort. Results show a statistically significant relationship between building fabric heat capacity and subjective comfort (thermal perception χ2(1)=3.78, p=0.05 and overall comfort χ2(1)=4.37, p<0.05). Heavyweight buildings are reported to be more comfortable than lightweight buildings. Providing careful integration with building management, this insight may have implications on the adoption of thermal mass in new and retrofit buildings.